Project Details
Projekt
Bacterial Phytochromes for Bimodal Control of Cyclic Nucleotide Signaling
Applicant
Professor Dr. Andreas Möglich
Subject Area
Biochemistry
Biophysics
Biophysics
Term
from 2015 to 2024
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 267795153
Phytochromes (Phy) are a class of sensory photoreceptors orchestrating biological responses to red and far-red light. Photon absorption drives the bidirectional photoconversion between the Phy Pr and Pfr states that differ in biological activity. Whereas plant Phys exert downstream re-sponses primarily through light-dependent protein:protein interactions, bacterial phytochromes (BphP) excel in regulating enzymatic activity. The light-sensitive photosensory core modules (PCM) of BphPs can be coupled to intrinsically light-inert enzymes to bestow light sensitivity on them. Nucleotidyl cyclases and phosphodiesterases (PDE), that make and break the universal second messengers 3’, 5’-cyclic adenosine and guanosine monophosphate, have thus been sub-jected to the control by red and far-red light. To date, the catalytic turnover and the degree of light regulation are however limited. Building on recent advances in the engineering and mechanism of BphPs, this proposal hence seeks to devise enhanced light-regulated enzymes for the precise bimodal control of cyclic nucleoside monophoshate (cNMP) levels and downstream physiological processes. BphP-based cNMP cyclases and PDEs are obtained by modular replacement of PCMs and effectors, by variation of the linker conjoining these modules, and by generating hybrid PCMs. Screening platforms efficiently identify improved variants and allow their enzymatic char-acterization and structural rationalization. Deployed in mammalian cells, candidate BphP cyclases and PDEs optogenetically regulate cNMP levels and ion-channel opening. To prospectively ena-ble superior spatial resolution and better tissue penetration, we investigate the actuation of BphPs by two-photon absorption with micrometer radiation. Improved BphP-based cNMP cyclases and PDEs empower optogenetics, since they do not require exogenous chromophores, they support bidirectional switching for enhanced resolution in time and space, and they respond to compara-tively long wavelengths that penetrate tissue more deeply. Moreover, the identification of rules for the design of BphP-based actuators stands to grant general insight into signal transduction and informs the engineering of light-regulated receptors.
DFG Programme
Research Grants
International Connection
Israel, Sweden
